Devices which agitate articles within a rotating drum in the presence of a fluid are known. For example, U.S. Pat. No. 5,350,323, discloses a dual drum mixer which can be used to mix, homogenize or react at least two components. The device is a container made of two separately driveable pipe lengths adjacent to one another. The container is sealed, with fluid being injected into the container through its longitudinal axes. The device is limited in use in that fluid entry is only through its axes and the fluid must be sealed within the container in order for proper mixing or agitation to occur.
In agitation devices such as conventional washing machines, a perforated drum is used to contain articles as they are agitated in the presence of water and detergent in order to remove dirt. The dirt is displaced into the water, and the water is removed from the drum by passing through the perforations. In front-loading washing machines, agitation is caused by the rotation of the drum about a generally horizontal axis so that the articles tumble over one another and rub against each other and against the walls of the drum. However, the rotational speed of the drum is limited because, if the speed is too high, the articles will merely be pressed under centrifugal forces against the interior walls of the drum. The articles then rotate with the drum and no agitation with respect to the drum or with respect to other articles is achieved. The amount of agitation which can be applied to the articles by front-loading washing machines is therefore limited. This means that, in order to achieve a specific standard of cleanliness, the machine must operate for a minimum period of time.